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From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: mingo@redhat.com, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
	linux-kernel@vger.kernel.org, kprateek.nayak@amd.com,
	pauld@redhat.com, efault@gmx.de, luis.machado@arm.com
Subject: Re: [PATCH 03/10 v2] sched/fair: Add new cfs_rq.h_nr_runnable
Date: Mon, 2 Dec 2024 10:54:01 +0100	[thread overview]
Message-ID: <20241202095401.GJ24400@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20241129161756.3081386-4-vincent.guittot@linaro.org>

On Fri, Nov 29, 2024 at 05:17:49PM +0100, Vincent Guittot wrote:
> With delayed dequeued feature, a sleeping sched_entity remains queued in
> the rq until its lag has elapsed. As a result, it stays also visible
> in the statistics that are used to balance the system and in particular
> the field cfs.h_nr_queued when the sched_entity is associated to a task.
> 
> Create a new h_nr_runnable that tracks all queued and runnable tasks and
> use it when balancing the load on the system.
> 
> h_nr_runnable will be used in several places to make decision on load
> balance:
> - PELT runnable_avg
> - deciding if a group is overloaded or has spare capacity
> - numa stats
> - reduced capacity management
> - load balance
> - nohz kick
> 
> It should be noticed that the rq->nr_running still counts the delayed
> dequeued tasks as delayed dequeue is a fair feature that is meaningless
> at core level.

Since you're doing a v3, could you please split this into 2 patches, one
adding the accounting, and then a separate patch making use of it?

  reply	other threads:[~2024-12-02  9:54 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-29 16:17 [PATCH 0/10 v2] sched/fair: Fix statistics with delayed dequeue Vincent Guittot
2024-11-29 16:17 ` [PATCH 01/10 v2] sched/eevdf: More PELT vs DELAYED_DEQUEUE Vincent Guittot
2024-11-29 16:17 ` [PATCH 02/10 v2] sched/fair: Rename h_nr_running into h_nr_queued Vincent Guittot
2024-11-29 16:17 ` [PATCH 03/10 v2] sched/fair: Add new cfs_rq.h_nr_runnable Vincent Guittot
2024-12-02  9:54   ` Peter Zijlstra [this message]
2024-12-02  9:57     ` Vincent Guittot
2024-11-29 16:17 ` [PATCH 04/10 v2] sched/fair: Removed unsued cfs_rq.h_nr_delayed Vincent Guittot
2024-11-29 16:17 ` [PATCH 05/10 v2] sched/fair: Rename cfs_rq.idle_h_nr_running into h_nr_idle Vincent Guittot
2024-11-29 16:17 ` [PATCH 06/10 v2] sched/fair: Remove unused cfs_rq.idle_nr_running Vincent Guittot
2024-11-29 16:17 ` [PATCH 07/10 v2] sched/fair: Rename cfs_rq.nr_running into nr_queued Vincent Guittot
2024-11-29 16:17 ` [PATCH 08/10 v2] sched/fair: Do not try to migrate delayed dequeue task Vincent Guittot
2024-11-29 16:17 ` [PATCH 09/10 v2] sched/fair: Fix sched_can_stop_tick() for fair tasks Vincent Guittot
2024-11-29 18:26   ` K Prateek Nayak
2024-12-02  9:18     ` Vincent Guittot
2024-11-29 16:17 ` [PATCH 10/10 v2] sched/fair: Fix variable declaration position Vincent Guittot
2024-11-29 18:30   ` K Prateek Nayak
2024-12-02  9:19     ` Vincent Guittot
2024-12-01 13:30 ` [PATCH 0/10 v2] sched/fair: Fix statistics with delayed dequeue Mike Galbraith
2024-12-02  9:17   ` Vincent Guittot
2024-12-02  9:23     ` Luis Machado
2024-12-02  9:59       ` Vincent Guittot
2024-12-02 13:52         ` Dietmar Eggemann
2024-12-02  9:58     ` K Prateek Nayak
2024-12-02 11:42       ` Vincent Guittot
2024-12-02 14:24         ` Vincent Guittot
2024-12-02 18:34     ` Mike Galbraith

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